Question

\(\dfrac{2}{3}\)-\(\dfrac{5}{7}\)+\(\dfrac{22}{21}\)

Answer 1

\(=\dfrac{14}{21}-\dfrac{15}{21}+\dfrac{22}{21}\\ =\dfrac{-1}{21}+\dfrac{22}{21}\\ =\dfrac{21}{21}=1\)

Answer 2

=\(\dfrac{14}{21}\)-\(\dfrac{15}{21}\)+\(\dfrac{22}{21}\)

=\(\dfrac{21}{21}\)

=1

Answer 3

Quy đồng nhé mn 

Answer 4

=14 phần 21−15 phần21+ 22 phần21

= −1 phần21+22 phần 21

=21 phần 21=1